cast<T> function

T? cast<T>(dynamic input)

Implementation

T? cast<T>(dynamic input) {
  if (input == null) {
    return null;
  }

  try {
    final typeString = T.toString();
    if (typeString.startsWith(_listPrefix)) {
      if (input is! List) {
        throw TypeError();
      }

      if (typeString == "List<int>") {
        return List<int>.from(input) as T;
      } else if (typeString == "List<num>") {
        return List<num>.from(input) as T;
      } else if (typeString == "List<double>") {
        return List<double>.from(input) as T;
      } else if (typeString == "List<String>") {
        return List<String>.from(input) as T;
      } else if (typeString == "List<bool>") {
        return List<bool>.from(input) as T;
      } else if (typeString == "List<Map<String, dynamic>>") {
        final objects = <Map<String, dynamic>>[];
        (input as List<Map<String, dynamic>?>).forEach((o) {
          if (o != null) {
            if (o is! Map<String, dynamic>) {
              throw TypeError();
            }
            objects.add(o);
          }
        });
        return objects as T;
      }
    } else if (typeString.startsWith(_mapPrefix)) {
      if (input is! Map) {
        throw TypeError();
      }

      final inputMap = input as Map<String, dynamic>;
      if (typeString == "Map<String, int>") {
        return Map<String, int>.from(inputMap) as T;
      } else if (typeString == "Map<String, num>") {
        return Map<String, num>.from(inputMap) as T;
      } else if (typeString == "Map<String, double>") {
        return Map<String, double>.from(inputMap) as T;
      } else if (typeString == "Map<String, String>") {
        return Map<String, String>.from(inputMap) as T;
      } else if (typeString == "Map<String, bool>") {
        return Map<String, bool>.from(inputMap) as T;
      }
    }

    return input as T;
  } on TypeError {
    throw TypeCoercionException(T, input.runtimeType);
  }
}